Something I plan to do this winter is open up my UPP hard cased triangle pack to check each parallel group voltage, then inspect the cells and construction. I have two UPP packs and both have worked well, but I've seen posts about the construction of some of their packs, so I'm curious to see what's going on inside.
Since some of the posts point to lack of sufficient nickel strips for the amount of current that needs to flow, my question is related to how that might affect voltage sag. I get a decent amount of sag when pulling current at or above the continuous rating of the cells when accelerating, and some sag below that level of discharge. I assume most of that comes from the cells, but wonder how much sag contribution the conductors add, if insufficient. In addition, resistance goes up as the conductors heat up, so maybe the impact is magnified under higher loads.
I've been researching spot welders for a future battery project, but if there's an ability to improve my existing pack performance, while getting some practice, I'd move that purchase up higher in the queue.
Since some of the posts point to lack of sufficient nickel strips for the amount of current that needs to flow, my question is related to how that might affect voltage sag. I get a decent amount of sag when pulling current at or above the continuous rating of the cells when accelerating, and some sag below that level of discharge. I assume most of that comes from the cells, but wonder how much sag contribution the conductors add, if insufficient. In addition, resistance goes up as the conductors heat up, so maybe the impact is magnified under higher loads.
I've been researching spot welders for a future battery project, but if there's an ability to improve my existing pack performance, while getting some practice, I'd move that purchase up higher in the queue.